Question: If $x \circledcirc y = x-5y$ and $x \triangleleft y = 4x-3y$, find $(2 \triangleleft 1) \circledcirc 6$.
First, find $2 \triangleleft 1$ $ 2 \triangleleft 1 = (4)(2)-(3)(1)$ $ \hphantom{2 \triangleleft 1} = 5$ Now, find $5 \circledcirc 6$ $ 5 \circledcirc 6 = 5-(5)(6)$ $ \hphantom{5 \circledcirc 6} = -25$.